The Pilot Core B will support one of the principal mechanisms by which the Boston Roybal Center (BRC) will achieve its overarching goal to develop and test behavior change strategies that promote healthy aging, especially for persons at high risk for poor health outcomes. The thematic focus of the BRC is on novel interventions to increase physical activity in vulnerable middle-aged and older adults. The Pilot Core will achieve this goal by supporting a group of innovative and scientifically rigorous pilot studies that will enhance our knowledge base, inform each other with new research methodologies and tools, and ultimately work collaboratively to develop the pilot data and experience necessary to conduct future full-scale clinical trials. The Pilot Core will leverage the knowledge gained by each project, incrementally enriching our conceptual model, and ultimately developing successful interventions to achieve health-promoting behavior change in at-risk populations. The specific aims of the Core are 1) To solicit, select, and support 4-6 of the most meritorious pilot studies each year that advance the BRC goals. These pilot studies will be solicited from among postdoctoral trainees, junior faculty, and established investigators of all racial and ethnic backgrounds who are working in participating BRC institutions. 2) To use the knowledge and skills gained by each pilot project to develop new research grants that test behavior change strategies to promote healthy aging in people at risk of poor health outcomes. We will also share results and plan ancillary studies by conducting monthly interactive seminars, and hosting an annual Visiting Scholar and Scientific Dinner focused on mechanisms to achieve sustainable health-promoting behavior changes. 3) To enhance the progress of pilot awardees' research projects by requiring the awardees to present their work at monthly seminars and External Advisory Committee meetings, and conducting biannual Center meetings between pilot investigators. Center faculty, and Core A and B leaders. 4) To assure the scientific integrity of our research and the safety of human subjects. The extensive research and administrative experience of the Co-Leaders and large pool of collaborating, investigators at participating institutions will help assure the Core's success. The Pilot Core will work closely with the Management and Administrative Core to make sure the BRC operates smoothly and fulfills its aims.